Water heating

This page is about hot water systems in homes & buildings.

Types

• solar thermal panels
• electric water heating
• natural gas water heating

Energy use

49'C is considered the ideal hot water temperature. Anything hotter is a safety hazard (scalding). If water is coming in to the building at a typical 9'C, then that's a 40 degree (kelvin) difference.

Physics shows how much energy it takes to heat the water: Same calculation shown in multiple different units:

Electricity water_specificheat * waterdensity * 40 kelvin kilowatt hours / liter (calculation loading)

British Thermal Units water_specificheat * waterdensity * 40 kelvin btu / liter (calculation loading)

Fuel burned to heat each gallon of water (American units) water_specificheat * waterdensity * 40 kelvin teaspoons gasoline / gallon (calculation loading)